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evaluation of the overall traffic noisip, this.analysis lis misleading. A typical noise analysis for traffic no-ise impacts would first.evaluate.the.-existing traffic -noise levels-and'compare-them.to-the siandard, and then evaluate the existing+ project noise levels to show the comparison. The BAC report estimated the project-related truck trips to result in an interior Ldn of 38 dB at a distance of 60 fed. J.-c. brtnnan & Msociates, Inc. utilized the Federal Highway, Administration (FHW- A RD77-108) traffic noise prediction model to evaluate the:project-related truck. trufflW.-noise levels along E. River ko4d. The-inputs assi.imcd 248 total truck trips, with 66 of those trips 0-0cuiT.1fig ,during the daytime hours. R iispitne.8'. a speed of'40 vaph (This is probably underestiinatirig the actual travel Speqds). The FUWA ttaffic noise prediction model restifted in an interior Ldn of dBA. 17, Page 3.4-of the BAC report provide.s a discussion "Traffic Noise Impacts Relative? to Eifiktirig Nighttime-Hautly Noise Levels Witkout the Project".. This analysis seems to indicate That-there is no significant Oise impact due to truck traffic q5 it is cobipared to the ambient noise environment. Based upon the BAG.rqQrt,' the project could typically result in 26 hourly truck Based upon Tabl-e,-6 of the BAC report, (lie average measured hourly background noise levels during the nighttime periods rangjA between 59 dBA L.eq and 62 dBA Leq at a distance of 60 feet from the centetline(Site 4). This.s corresponds with the closest building fagade to -the roadway,as.stated in the BAC report. if you use,the lowest SHL value shown F� in the BAC report.for truck passbys(79 dRA) at 60 feet, the Leq associated with the 26 trucks. would be 62 dBA. Therefore, the nighttime noise levels would increase between 3 dBA and 4 dBA Leq. Based upon the MON-criteria shown -in Table 3 of the report,this would result in a'signiftant increase:in.noise levels. What.the analysis does not nienil nj is,that :the increase in noise levels, which trigger a.significaa impact is bused upon an increase in noise levels of the-sarne .0haractcr.6 So; ifthe aihbient noise during the nighttime period is not a function of truck traffic, the increase in noise levels due to truck traffic, could be more .annoying than indicated. 1,8. Page 29 of the BAC report provides an Analysis of Potential Project Noise Impacts. Asphd.it Plant irnpai;ts are considered less than significant. Based upon our review, as described earlier in this review, the BAC report states that thizy utilize the noise measurement data collected at Sites A and B to isolate the asphalt plant noise levels. This process was used to determine the potential noise levels during nighttime operations. Once again, the noise measurement locations do not accurately represent potential noise levels at the elevated residences. This is due to the fact that the noise -measurement location used for evaluating the asphalt plant operations was F